1. Field of the Invention
The present invention relates to a driving apparatus that applies a driving signal to a piezoelectric element to move a movable body.
2. Description of the Related Art
The mechanical displacement obtained by the piezoelectric element is relatively minute. Therefore, a driving apparatus using the piezoelectric element is preferably used as actuators which require accuracy and also precise control. As an example of applying the driving apparatus which uses the piezoelectric element, for instance, a driving apparatus which moves an optical system included in an imaging device and the like are exemplified.
However, for the imaging device applying the driving apparatus like the above, operating noises are generated when driving, and that sometimes causes a problem. Specifically, like video recording, when taking images along with sounds, the operating noises generated when driving optical systems interfere with taking environmental sounds, and this has become a problem. As conventional technologies for reducing operating noises of the driving apparatus, for instance, technologies that gradually increases or decreases a driving pulse voltage and the like have been proposed.
Japanese Published Unexamined Application No: H9-191676
For the conventional technologies that gradually increases or decreases the driving pulse voltage, it is effective for reducing the operation noises. However, there is a problem that the movement speed of a movable body significantly decreases and also responsiveness to the control signal significantly decreases.